Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark this as read-only and idempotent, and the description adds valuable behavioral details: a 422 refusal with no charge for empty windows, partial coverage before the archive's first date, and per-call pricing. No contradiction with annotations exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is information-dense with no filler; every sentence contributes to selection, invocation, or cost understanding. The middle sentence on attribution is slightly convoluted, but overall it is appropriately sized and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no output schema, the description gives a useful sense of what rows contain—attribution type, first archive observation, and early-traction evidence—and covers error behavior. It stops short of specifying the full return shape, but the essential selection and invocation context is present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already documents both parameters completely, so baseline is 3. The description references a date and window indirectly but does not add meaningful parameter-specific semantics beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool lists x402 services first listed since a given date, with first archive observation and early-traction evidence. It also defines the attribution model and row content, which distinguishes it from the sibling analytics tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The opening clause establishes a clear use case: finding services newly listed since a date. It does not explicitly contrast with sibling tools like x402_trending_services or x402_top_movers, but the unique purpose and sibling names make the distinction reasonably clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.